diff --git a/src/music/convert.py b/src/music/convert.py
index 762f2a6..bf714d0 100644
--- a/src/music/convert.py
+++ b/src/music/convert.py
@@ -11,19 +11,23 @@ from multiprocessing import Pool
 logger = logging.getLogger(__name__)
 
 
-def convert_audio_file(args):
-    cmd, output_tmp, output_path = args
+def run_task(args):
+    task = args[0]
 
     subprocess.run(cmd, shell=True)
-    os.makedirs(output_path.parent, exist_ok=True)
-    shutil.move(output_tmp, output_path)
-
+    os.makedirs(task.output_path.parent, exist_ok=True)
+    shutil.move(task.output_tmp, task.output_path)
 
 class ConversionConfig(NamedTuple):
     input_dir: Path
     output_dir: Path
-    output_fmt: str
-    input_fmt: str
+    output_ext: str
+    input_ext: str
+
+class Task(NamedTuple):
+    cmd: str
+    output_tmp: Path
+    output_path: Path
 
 
 def _get_converted_path(input_path: Path, config: ConversionConfig):
@@ -33,15 +37,34 @@ def _get_converted_path(input_path: Path, config: ConversionConfig):
     """
 
     relative_path = input_path.relative_to(config.input_dir)
-    output_filename = str(input_path.stem) + f".{config.output_fmt}"
+    output_filename = str(input_path.stem) + f".{config.output_ext}"
     output_filename.replace("'", "")
     output_path = config.output_dir / relative_path.parent / output_filename
     return output_path
 
-
-def get_files_recursive(search_path: Path, extension: str):
+def get_files_recursive(search_path: Path,
+                        extension: str) -> list[Path]:
     return list(search_path.rglob(f"*.{extension}"))
 
+def ffmpeg_convert(input_path: Path,
+                       output_dir: Path,
+                       output_ext: str) -> str:
+    output_tmp = output_dir / (str(uuid.uuid4()) + f".{output_ext}")
+    cmd = f"ffmpeg -i '{input_path}' -ab 320k -map_metadata 0 -id3v2_version 3 '{output_tmp}'"
+
+def build_conversion_tasks(input_files: list[Path],
+                           output_files: list[Path],
+                           config: ConversionConfig) -> list[Tasks]:
+    tasks = []
+    for input_path, output_path in zip(input_files, output_files):
+        cmd = get_conversion_cmd(input_path, config.output_dir, config.output_ext)
+        tasks.append((cmd, output_tmp, output_path))
+    return tasks
+
+def get_unconverted_files(input_files: list[Path],
+                          config: ConversionConfig) -> list[Path]:
+    output_files = [_get_converted_path(f, config) for f in input_files]
+    return [f for f in output_files if not f.exists()]
 
 def convert(config: ConversionConfig):
 
@@ -51,26 +74,13 @@ def convert(config: ConversionConfig):
     os.makedirs(config.output_dir, exist_ok=True)
 
     input_files = get_files_recursive(
-        config.input_dir.resolve(), config.input_fmt
-    )
-    output_files = []
-    for input_file in input_files:
-        candidate_output = _get_converted_path(input_file)
-        if not candidate_output.exists():
-            output_files.append(candidate_output)
-    print(output_files)
-
-    tasks = []
-    for idx, (input_path, output_path) in enumerate(zip(input_files, output_files)):
-
-        logger.info("Converting file %d of %d", idx, len(input_files))
-
-        output_tmp = self.output_dir / (str(uuid.uuid4()) + f".{self.output_fmt}")
-        cmd = f"ffmpeg -i '{input_path}' -ab 320k -map_metadata 0 -id3v2_version 3 '{output_tmp}'"
-        tasks.append((cmd, output_tmp, output_path))
+        config.input_dir.resolve(), config.input_ext)
+    output_files = get_uncoverted_files(input_files, config)
 
+    tasks = build_conversion_tasks(input_files, output_files, config)
+    
     with Pool(10) as p:
-        p.map(convert_audio_file, tasks)
+        p.map(run_task, tasks)
 
 
 def move(input_dir: Path, output_dir: Path):